Combination stripper and blowout preventer



June 27, 1967 G. c. PRICHARD 3,328,040

COMBINATION STRIPPER AND BLOWOUT PREVENTER Filed March 23, 1964 I vINVENTOR. F I G/en C. Pr E/Iard ATTORNEY United States Patent 3,328,040COMBINATIGN STRIPPER AND BLOWOUT PREVENTER Galen C. Priclrard, 121Industrial Road, Perryton, Tex. 79070 Filed Mar. 23, 1964, Ser. No.353,971 8 Claims. '(Cl. 277-73) This invention relates to improvementsin oil and gas Well apparatus and more particularly, but not by way oflimitation, to a combination stripper and blow-out preventer forutilization during the completion of a well or during servicing orworkover operations on a producing Wel-l.

Subsequent to the drilling of an oil or gas Well bore, the well isprepared for production of fluid in the manner best suited to thesubsurface conditions. Perhaps the most common completion methodcomprises the setting of a final string of easing, known as the oilstring, which usually extends from the surface of the ground to the topof or through the subsurface producing zone or oil sand. The oil stringis usually then cemented in place and perforated in the vicinity of theproducing zone in order that the Well fluid may enter the casing, Sincethe casing normally remains in the well bore for an extended period oftime and repair or replacement thereof is expensive, it is the usualpractice to insert a tubing string through the casing and suspend thetubing therein in order that the well fluid may flow therethrough to thesurface of the well bore. When the normal pressures Within the well boreare insufficient for elevating the fluid through this central tubing,commonly called the flow string, a pump or other means may be supportedby the tubing for providing -an artificial lift of the fluid through thetubing. This flow string may be more easily removed from the well borefor repair work than the cemented casing.

In order to conserve steel materials, many well completion operationstoday utilize relatively small diameter casing for the oil string ascompared to the larger casing, and this smaller casing is often referredto as tubing. Of course, in these installations, the flow string is alsoof a smaller diameter. Since there is frequently excessive pressurewithin the well bore, it is desirable to provide a packing device, knownas a blowout preventer, around the inner tubing or flow string duringthe installation thereof within the set casing. This substantiallyprecludes the accidental escape of high pressure from the surface of thewell. In addition, it is usually desirable to provide a stripper aroundthe flow string for bearing against the outer periphery thereof as thetubing is lowered within the casing.

The flow string and any pumping equipment, or other artificial liftapparatus carried thereby, is subject to deterioration during theproduction of the well fluid and it often becomes necessary to pull theflow string as well as the pumping equipment from the bore in order torepair or replace portions thereof. During this operation, usuallyreferred to as stripping, it is considered necessary to install ablowout preventer at the surface of the well to preclude loss of fluiddue to excessive pressures in the bore. In addition, it is usuallynecessary to provide a stripper device around the flow string, or suckerrods, or i any other tubing being removed from the well bore during theremedial work or servicing of the well. As a result, it is usuallynecessary to install at least two tools or devices in connection withthis portion of the servicing operation or in the well completionoperations, and in many instances, three or four separate tools arerequired.

The present invention contemplates a novel combination stripper andblowout preventer which may be utilized in both well completion Work andremedial or workover opera-trons. The novel tool may be used in lieu ofthe three or four tools usually required in these circumstances. Thetool comprises a housing which may be secured directly to the well heador other suitable surface connection member and is provided with aplurality of packermembers of a particular inner and outer configurationfor packing off the annular space between the flow string and thehousing. Means is carried by the housing which may be eithermechanically or fluid operated for longitudinally compressing thepacking members to as sure an eflicient sealing 'around the flow string,sucker rods, or the like, as well as the ,inner periphery of thehousing. The particular configuration of the sealing or packing memberis such that the inner periphery thereof will close completely if thereis no tubing inserted therethrough, thus providing a sealing off of anopen hole, if desired. The inner periphery of the packing membersfunctions to strip the tubing when either putting the tubing in the holeor pulling it out .of the hole. Thus, this one novel tool may beutilized for at least three separate and independent functions, namelyas a blowout preventer, a stripper, or as a complete shut-off blowoutpreventer. The novel combination blowout preventer and stripper issimple and eflicient in operation and economical and durable inconstruction.

It is an important object of this invention to provide a single tool foran oil well,installation which may be uti lized in lieu of a pluralityof conventional tools presently required in certain well boreoperations.

It is another object of this invention to provide a combination stripperand blowout preventer having packing members of a particularconfiguration for efliciently sea-ling the annular space between anouter housing and the flow string, or the like, of a producing well.

Another object of this invention is to provide a novel combinationstripper and blow-out preventer for oil or gas wells which may beoperated either by fluid power or manually.

Still another object of this invention is to provide a novel tool forutilization with an oil or gas, well to perform a plurality of functionsin a single unit.

Other and further objects and advantageous features of the presentinvention will hereinafter more fully appear in connection with adetailed description of the drawings in which:

FIGURE 1 is an elevational view partly in section depicting acombination stripper and-blowout preventer embodying theinvention.

. FIGURE 2 is a perspective view depicting a general arrangement forfluid operation of the device depicted in FIGURE 1.

Referring to the drawings in detail, reference character 10 generallyindicates a combination stripper and blowout preventer device comprisinga substantially cylindrical housing or body 12 having a threaded stemportion 14 provided at one end thereof for connection with a well head(not shown) or the like, normally found at an oil or gas Well site. Theopposite end 16 of the housing 12 is open for a purpose as will behereinafter set forth and an outwardly extending circumferential flange18 is provided on the outer periphery of the housing 12 spaced from theopen end 16. A central bore 20 extends longitudinally through thehousing 12 and is enlarged at 22 to provide an inwardly directed annularshoulder 24 for supporting a plurality of stacked resilient membersgenerally indicated at 26. A radially extending port 28 is providedinthe housing 12 to provide communication between the interior of the bore20 and the exterior of the housing 12. A suitable threaded connectionmember or collar 30 may be secured on the outer periphery of the housing12 in any suitable manner (not shown) and in alignment with the bore 28for receiving a suitable fitting (not shown) to permit discharge of wellfluid from the bore 20 as is well known.

A cylindrical piston 32 is slidably disposed in the open end 16 of thehousing 12 and the lower end 34 thereof bears against the uppermostresilient member 26 as clearly shown in FIGURE 1. A follower cap membergenerally indicated at 36 is slidably [disposed around the piston 32 andcomprises an inner sleeve 38 concentrically arranged with an outersleeve 40 for receiving the piston 32 within the annular space 42therebetween. The upper end of the piston 32, as shown in FIGURE 1, isprovided with an outwardly extending circumferential shoulder 44 wherebythe inner periphery of the piston 32 and outer periphery of the flange44 engages the sidewalls of the annular chamber 42 for guiding anyreciprocal movement of the piston 3-2 with respect to the follower 36 aswill be hereinafter set forth in detail. It is preferable to provide aplurality of longitudinally spaced annular sealing ring members 46 onthe inner periphery of the piston 32 to provide a sealing engagementwith the outer periphery of the inner sleeve 38 and a plurality ofspaced sealing rings 48 on the outer periphery of the flange 44 forsealing engagement with the inner periphery of the outer sleeve 40. Aninwardly directed annular shoulder 50 is provided on the inner peripheryof the piston 32 for engaging one end of the inner sleeve 38 in onerelative position there between. An annular ring 52 is removably securedto the lower end of the outer sleeve 40 in any well known manner such asby a plurality of threaded stud members 54. The ring 52 is preferably ofan outer diameter substantially equal to the outer diameter of thesleeve 40 and an inner diameter of a size for slidable engagement withthe outer periphery of the piston 32. The ring 52 provides a stop toengage the flange 44 for limiting the movement of the piston 32 in onedirection within the annular chamber 42.

A threaded aperture 56 is provided in the outer sleeve 40 for receivinga suitable fitting member 58 whereby fluid pressure may be injected intothe annular chamber 42 as will be hereinafter set forth. In addition, anoutwardly extending circumferential flange 60 is provided at the upperend of the follower member 36 and is provided with a plurality ofcircumferentially spaced apertures (not shown) disposed in substantialalignment with similarly spaced apertures (not shown) provided in theflange 18 of the housing 12. The flanges 18 and 60 may be interconnectedby means of a plurality of spaced stud members 62 extending through thealigned apertures and secured therein by suitable locking nuts 64 and 66as is well known.

The packing members 26 may be constructed from any suitable resilientmaterial such as rubber, neoprene, or the like, and is provided with acentral bore 68 extending therethrough adapted to engage the outerperiphery of the tubing string or flow string (not shown) with which theapparatus is being utilized. The bore 68 is enlarged at 70 and thecross-sectional configuration of the enlarged portion 70 is preferablyarcuate as clearly shown in the drawings. The outer periphery of theresilient member 26 may be chamfered at both ends as shown in 72 and 74and an annular recess 76 is provided around the outer periphery of theresilient member 26 preferably substantially centrally disposed betweenthe chamfered portions 72 and 74. The cross-sectional configuration ofthe recess 76 is preferably arcuate as shown in FIGURE 1 and the outerperiphery of the resilient member 26 disposed between the recess 76 andthe opposite chamfered 72 and 74 is preferably substantially straightfor engaging the inner periphery of the housing 12. The relatively longinternal bore 68 provides an efficient sealing around the flow string(not shown), sucker rods (not shown), or the like, extending throughoutthe device 10. The outer periphery of the resilient members 26 providesan efiicient sealing with the housing 12. The bottom and top surfaces 78and 80, respectively, of the resilient members 26 as shown in FIGURE 1are preferably substantially flat whereby a plurality of the packingmembers 26 may be superimposed within the housing 12. Of course, thelowermost packing member 26 is supported by the shoulder 24 and theuppermost packing 26 is engaged by the piston 32 whereby longitudinalforce or pressure may be exerted on the plurality of packing members 26disposed within the housing 12.

Referring now to FIGURE 2, fluid may be supplied to the annular chamber42 of the follower member 36 by means of suitable surface equipment asshown diagrammatically herein. A fluid reservoir 80 may be mounted on asuitable base 82 which in turn is installed in the proximity of theapparatus 10 in any well known manner (not shown). Of course, thereservoir 80 and base structure 82 may be separated from the apparatus10 by as much as fifty feet, if desired, and is not limited to anyparticular spacing or position with respect to the device 10. A suitablepump 84 may be mounted on the base structure 82 and connected with thereservoir 80 in any well known manner (not shown) for moving the fluidfrom the reservoir 80 through an outlet conduit 86 which extends fromthe pump 84 to the fitting 58. The actuation of the pump 84 draws thefluid from the reservoir 80 through the conduit 86 and into the annularchamber 42 of the follower cap 36. The fluid in the chamber 42 acts uponthe outer surface 88 on the piston 32 for urging the piston 32 in adirection toward the packing members 26. The downward movement of thepiston 32 compresses the packings 26 and the particular configuration ofthe packings 26 causes the deformation thereof to greatly enhance thesealing between the flow string (not shown) and the inner periphery ofthe housing 12 as will be hereinafter set forth in detail.

Operation The combination stripper and blowout preventer may beinstalled around the flow string, sucker rods, or other tubular membersin a well bore (not shown) by threaded connection at 14 with the wellhead (not shown) or the like. With the novel tool 10, utilized inposition around the tubing or flow string, particularly tubing of arelatively small outer diameter, the packing members 26 will engage theouter periphery of the flow string and function as a blowout preventer.

Referring now to FIGURE 1, the plunger or piston 32 is depicted in theuppermost position with respect to the follower cap 36. A suitablefluid, such as oil, water, or the like, may be introduced into theannular chamber 42 above the piston 32 by means of the pump 84. As fluidis introduced into the chamber 42, an equal force will be exerted in alldirections against the sides of the chamber 42 and the outer end 88 ofthe piston 32. Since the follower 36 cannot move in an upward directionbecause of the connection with the flange 18, the force exerted on thepiston 32 will urge the piston downwardly against the resilient members26 to exert a longitudinal pressure thereon. This force exerted on thepackings causes the packings to deform in such a manner that theinternal bore 68 thereof is urged radially inward into a tight sealingengagement with the outer periphery of the tubing extendingtherethrough. In addition, the outer periphery of the packings 26 aresimultaneously urged radially outwardly to form an efficient sealingengagement with the inner periphery of the housing 12. This is actionenhanced by the annular groove 76 provided on the outer periphery of thepacking members 26. Even though considerable wear may occur to thepacking rings 26, particularly on the inner periphery thereof, anincreased longitudinal pressure by the piston 32 will maintain anefficient seal between the housing 12 and flow string to provide aprolonged and etficient life for the packing 26.

Of course, well fluid may enter the casing 12 through the bore 20 andsince it cannot move upwardly around the resilient members 26, the wellfluid will be directed outwardly through the bore 28 and collar 30 fordischarge or accumulation in auxiliary equipment as is well known. Whenthe well tubing or flow String is being pulled from the well bore (notshown), the inner bore 68 of the packing members 26, being relativelylong, provide an eflicient stripping of the outer periphery of thetubing. In addition, when the tubing or flow string has been completelyremoved from the well, the inner bore 68 of the packing members 26 willcontract radially inward to completely close the bore upon theapplication of suflicient fluid pressure in the chamber 42, thus sealingoff the open hole.

In the event that it is desired to provide manual operation of thedevice 10, the piston 32 may be moved downwardly by rotation of thestuds 62 extended between the flanges 18 and 60. In this instance, ahydraulic fluid will be injected into the chamber 42 and sealed thereinby either plugging of the aperture 56 or through the use of the fitting58 which may be of any suitable type for checking any back flow of thefluid or precluding passage of the fluid in reverse direction from thechamber 42. The hydraulic fluid trapped within the annular space 42 willprovide a lock between the end 88 of the piston and the closed upper endof the chamber 42 and thus, the downward movement of the cap 36 uponrotation of the studs 62 in the proper direction will be transferred tothe piston 32 regardless of position thereof with respect to the innersleeve 38. It is to be noted that the engagement between the flange 44and the ring 52 limits the movement of the piston 32 in one directionand engagement of the shoulder 50 with the inner sleeve 38 limits themovement of the piston 32 in an opposite direction.

It has been found that the resilient members 26 provide an efficientseal at pressures up to 6,000 pounds per square inch when utilized as ablowout preventer, It has also been found that the packing members willwithstand pressures up to 3,000 pounds per square inch while rotatingthe flow string through a time period of 24 hours and using only one setof the packers. In addition, the apparatus has been tested and found towithstand pressures up to 3,000 pounds per square inch when the flowstring has been removed from the well and the device is being utilizedas a complete shut-off blowout preventer.

From the foregoing, it will be apparent that the present inventionprovides a novel combination stripper and blowout preventer which may beused for eflicient stripping of wire lines, sucker rods, relativelysmall diameter tubing, or the like, when these rods or tubing member-sare either coming in or going out of a well bore under pressure.Furthermore, the overall structure of the device is such that the uppersurface thereof can support the spider or slips when these devices arein use in connection with the well operation. The resilient membersfunction efficiently to perform multiple operations and are particularlydesigned and contracted to provide a prolonged useful life therefor. Thedevice may be either manually operated or hydraulically operated byremote control, if desired. The novel combination stripper and blowoutpreventer provides a plurality of functions in a well servicing or wellcompletion operation through the use of a single unit. The novel tool issimple and eflicient in operation and economical and durable inconstruction.

Changes may be made in the combination and arrangement of parts asheretofore set forth in the specification and shown in the drawings, itbeing understood that any modification in the precise embodiment of theinvention may be made within the scope of the following claims, withoutdeparting from the spirit of the invention.

What is claimed is:

1. In a tool of the character described, a housing, resilient meansdisposed within and supported by the housing, cylindrical piston meansslidably disposed within the housing and in engagement with one of saidresilient means, and follower means cooperating with the slidable meansfor urging the slidable means in a direction toward the resilient meansto apply pressure thereagainst, said follower means including a pair ofspaced cylindrical sleeves for receiving the piston means therebetween,said resilient means being of a configuration whereby the inner andoute-r peripheries thereof expand in opposite radial directions upon theapplication of said pressure thereagainst.

2. A combination stripper and blowout preventer comprising a housing, aplurality of resilient members supported within the housing, cylindricalplunger means slidably disposed within the housing and in engagementwith one of said resilient members, follower means secured to thehousing and engageable with the plunger means for urging the plunger ina direction toward the resilient members to apply pressure thereto, saidfollower member including a pair of spaced cylindrical sleeves forreceiving the plunger therebetween, and said resilient members beingdeformable upon the application of said pressure whereby the innerperiphery thereof is urge radially inwardly and the outer peripherythereof simultaneously is urged radially outwardly.

3. A combination stripper and blowout preventer comprising asubstantially cylindrical body, an inwardly directed annular shoulderprovided on the inner periphery of the body, a plurality ofsubstantially annular resilient members disposed within the body andsupported by the shoulder, a substantially cylindrical piston memberslidably disposed within the body and in engagement with one of theresilient members, a follower member having a pair of spaced concentricsleeves for receiving the piston therebetween and engageable with thepiston member, and means cooperating between the body and the followermember for urging the piston member in a direction toward the resilientmembers for compression thereof.

4. A combination stripper and blowout preventer as set forth in claim 3wherein each resilient member comprises a resilient body portion havinga substantially straight walled central bore extending therethrough, anenlarged portion provided at one end of the central bore, the outerperiphery of the body portion being provided with a substantiallycentrally disposed annular recess to facilitate deformation of thepacking member whereby the inner periphery thereof is urged radiallyoutwardly under compression.

5. A combination stripper and blowout preventer comprising asubstantially cylindrical body, an inwardly directed annular shoulderprovided on the inner periphery of the body, a plurality ofsubstantially annular packing members disposed within the body andsupported by the shoulder, a substantially cylindrical piston memberslidably disposed within the body and in engagement with one of thepacking members, a follower member engageable with the piston member andcomprising a pair of concentrically arranged sleeves having an annularspace therebetween for slidably receiving the piston, means for limitingthe movement of the piston in opposite longitudinal directions withinthe annular space, means for inserting a fluid within the annularchamber for acting on one end of the piston, and means cooperatingbetween the :body and the follower member whereby the piston may beurged in a direction toward the packing members by either fluid ormanual power for compression thereof.

6. A combination stripper and blowout preventer as set forth in claim 5wherein each packing member comprises a resilient body port-ion having asubstantially straight walled central bore extending therethrough, anenlarged recess portion provided at one end of the central bore, theouter periphery of the body portion being provided with a substantiallycentrally disposed annular recess to facilitate deformation of thepacking member whereby the inner periphery thereof is urged radiallyinwardly and the outer periphery thereof is urged radially outwardlyunder compression.

7. A combination stripper and blowout preventer comprising asubstantially cylindrical housing, an inwardly directed shoulderprovided on the inner periphery of the housing, a plurality ofsuperimposed resilient annular packing members disposed in the housingand supported by the shoulder, a substantially cylindrical pistonslidably disposed in the housing and in engagement with the uppermostpacking member, a follower member comprising a pair of conentricallyarranged sleeve members having an annular space therebetween forslidably receiving one end of the piston member therein, stop mean-scooperating between the follower member and piston member for limitingthe longitudinal movement of the piston with respect to the followermember, sealing means carried by the piston member for sealing againstthe sidewalls of the annular space, means for injecting a fluid into theannular space for action on the end of the piston disposed therein, anoutwardly extending circumferential flange provided on the outerperiphery of the housing, a complementary outwardly extending flangeprovided on the outer periphery of the follower member, and threadedstud means extending between the flanges for securing the follower tothe housing whereby the follower will urge the piston in a directiontoward the packing member by either fluid or manual power forlongitudinal compression of the packing members.

8. A combination stripper and blowout preventer as set forth in claim 7wherein each packing member comprises a resilient body portion having asubstantially straight walled central bore extending therethrough, anenlarged portion provided at one end of the central bore, the outerperiphery of the body portion being provided with a substantiallycentrally disposed annnular recess to facilitate deformation of thepacking member whereby the inner periphery thereof is urged radiallyinwardly and the outer periphery thereof is urged radially outwardlyunder compression.

References Cited UNITED STATES PATENTS 511,734 12/1893 Hoffstadt 277-1051,793,916 2/1931 Dykeman 277-208 X 2,243,439 5/1941 Pranger et .al.277-31 3,013,825 12/1961 Wilson 27 773 3,132,867 5/ 1964 Scaramucci277-4 X 3,168,320 2/1965 Sneed 1277-110 SAMUEL ROTHBERG, PrimaryExaminer.

1. IN A TOOL OF THE CHARACTER DESCRIBED, A HOUSING RESILIENT MEANSDISPOSED WITHIN AND SUPPORTED BY THE HOUSING, CYLINDRICAL PISTON MEANSSLIDABLY DISPOSED WITHIN THE HOUSING AND IN ENGAGEMENT WITH ONE OF SAIDRESILIENT MEANS, AND FOLLOWER MEANS COOPERATING WITH THE SLIDABLE MEANSFOR URGING THE SLIDABLE MEANS IN A DIRECTION TOWARD THE RESILIENT MEANSTO APPLY PRESSURE THEREAGAINST, SAID FOLLOWER MEANS INCLUDING A PAIR OFSPACED CYLINDRICAL SLEEVES FOR RECEIVING THE PISTON MEANS THEREBETWEEN,SAID RESILIENT MEANS BEING OF A CONFIGURATION WHEREBY THE INNER AND OUT-